flip/flop hub,tire rotation?
 

Newbie here. Just bought a 6ku urban track. Tires have an arrow for spin direction, when tire is flipped to single speed freewheel, arrow is going in wrong direction. Is this a problem with these kind of tires? Thanks in advance for any advice.

Complete non-issue.

yep, and if you care about speed/efficiency, I think I remember seeing that it takes under 5 w, more like 1-2.

Some tires are unidirectional because of an asymmetric tread pattern.
Usually, the tread pattern channels water away from the contact patch, just helps the tire roll faster in that one direction, corner better, and/or wear in a way that minimizes the removal of the tread pattern.
Tires that are uni-directional will only maximize/minimize the above properties while rolling in one direction.

That being said, you likely won't notice at all on dry pavement.
But if you keep riding it in the wrong direction, you might notice that your tread wears a little faster than it should.

So basically, just put it in the "correct" direction for the side that you ride the most.

tread is so tiny on road tires doubt it makes much difference which way they rotate. probably put arrows on there so people stop contacting them asking which way they should go.

It won't make a bit of difference.

Channeling water, cornering, resistance, watts, speed, wet or dry... it doesn't matter.

Like these guys are saying, it probably doesn't make a difference on really cheap tires.
But one thing that you will FOR SURE notice will be increased wear when riding it the "wrong" way.
Tires are not unidirectional unless the tread is asymmetrically "facing" one direction.
This means that regardless of how well they implement the above properties, they will 4sure wear fast more in one direction than the other.

Might be true for MTB tires that have very specific tread for front and back usage, but not for your typical road/urban tire.

Thanks for all the replies.